1. Field of the Invention
The invention relates to a device for reducing the risk of fire or delaying the ignition of flames in preferably large open or roofed storage tanks for combustible liquid media covered by floats, such as crude oil or the like, comprising a fixed cylindrical cavity as a tank for receiving the liquid, which tank is optionally provided with a further protective barrier surrounding it at a certain distance and serving as a collecting chamber in case of leakage.
2. Background Information
In case of afire, this device serves to delay the spreading until countermeasures can be taken or it is possible to make fire-fighting provisions. This is of particular importance, since valuable time passes before the discovery of a fire and the arrival of fire fighting vehicles.
It is known to discover or reduce a spreading of the fire through alarm devices and local fire protection devices, but this is not sufficient to delay the ignition of flames in large tanks. Provisions are made such as solid covers for oxygen deprivation, containment of the development of heat and the like, but the almost explosive ignition of flames cannot be stopped in most cases, in particular if the filling level of roofed tanks sinks so far that the ambient air promotes the fire or the collecting chamber surrounding the tank starts to fill through leakage.
It is also known to provide floating bodies, e.g., lined-up floats such as barrels, in order to decelerate a forming surface fire. It is, however, disadvantageous that with the line-up, gaps form that cannot delay the igniting fire, and the remedy must be evaluated as modest.
U.S. Pat. No. 5,377,765 A describes a device of a similar type in which a roof is used as a cover body. Depending on the degree of filling, this can be shifted in an axial direction and is provided with sealant on the peripheral edge.
U.S. Pat. No. 3,462,040 A shows an arrangement whereby cover bodies rest in a lined-up manner floating on the surface of the liquid and are secured by means of a net-like mat spread over them.
DE 197 03 308 A1 describes a safety netting of stretched material that can among other things be used to cover combustible liquids. This stretched material formed of irregular fibers is, however, not suited to reduce the risk of a fire, since a homogeneous covering is not present on account of outside influences, e.g., wind or the like.